The pistol feels very weak and feels like it has a mind of it's own sometimes. Tapping one key repeatedly as fast as possible and doing almost no damage isn't much fun. Only suggestion I can make atm is improve the damage a bit and give it a burst fire effect. That way you have a second to lift up your finger and either fire another shot or attack with the sword, will make air juggling also a lot more pleasant.

The handgun was designed in a similar fashion to DMC 1,3,4 which decided that it was more immersive to shoot 1:1 with the players inputs, I'm inclined to agree. God Hand is another game that uses a similar mechanic with the "Pummel" function though that was more an animation speed effect.

As for the pistols damage, you're not suppose to abuse the range to kill opponents, by convention no Hack 'n' Slash has ever made ranged attacks more effective than the melee attacks.

If you're worried about the pistol juggling damage if you look closely chances are the shots are actually missing. It's an interesting artifact from the game code that you can only shoot straight, so in order to maximize the hit rate of the pistols you have to wait until they are elevated in front of your gun.